PTFE-based aqueous dispersions

ABSTRACT

Compositions based on PTFE, homopolymer or modified, comprising for 100 parts of the component 1) PTFE: 1) an aqueous nanodispersion of said homopolymer or modified PTFE, having a primary particle diameter from 5 to 100 nm; 2) from 3 to 45 parts by weight of a surfactant or surfactant mixtures; 3) from 0.2 to 20 parts by weight of an organic or inorganic sequestrant, and optionally: 4) from 0 to 60 parts by weight of a solid lubricating compound.

The present invention relates to a (per)fluorinated substance for themetal surface coating, capable to form low thickness films, having thefollowing combination of properties:

-   excellent adhesion properties on steel and metals, for example    aluminum;-   low friction coefficient;-   crack free;-   good wear resistance;-   good scratch resistance;-   no modification of the finishing degree of treated metal surfaces.

Specifically the invention relates to PTFE or modified PTFE polymerswhich are used, under the form of their aqueous dispersions or latexes,to obtain films having the combination of the above properties andthicknesses from 0.3 to 10 micron, preferably from 0.5 to 5 micron,still more preferably from 1 to 3 micron.

It is known in the prior art that coatings of fluoropolymers, inparticular PTFE, obtained from the corresponding aqueous dispersions orlatexes, are used due to their low friction coefficient to obtainsurfaces having self-lubricating, antiadhesive and self-cleaningproperties, capable to operate at high temperatures having high thermalstability and low flammability. Said coatings are utilized in variousapplication, such for example kitchen utensiles, the industrialantiadhesion and the moving mechanical parts, etc. Howeverfluoropolymer-based coatings have the drawback to have a low adhesiontowards steel and metal surfaces in general.

In the prior art to overcome said drawback, the fluoropolymer filmadhesion to metal surfaces is obtained by mixing a fluoropolymer aqueousdispersion, for example PTFE, with hydrogenated resins capable to formfilms, for example polyamidic acid salts. In this way the compositionapplied on the support stratifies, and the hydrogenated resinconcentrates at the interphase with the support to give adhesion, whilethe fluoropolymer remains on the surface, giving to the obtained coatingthe antiadhesion properties. To obtain good results with said kind ofcomposition the metal support must be pretreated for example bysandblast and/or etching. Said process has the drawback to need apreliminary step to the film formation phase. Besides, the abovepretreatments cannot be used on precision mechanical parts, as gears,print rolls, etc., since for said mechanical parts the finishing andshape must not be modified.

To overcome said drawback in the patent application WO 96/13,556 aprimer is used, having a low content of a perfluorinated polymer, whichcan be applied also on untreated substrata. The used primer is formed bya mixture of PTFE, polyamidic acid salts and silicates or metal oxides.According to said patent application to obtain coatings havingantiadhesion properties various steps are required, applying successivefluoropolymer layers. Said repeated steps result disadvantageous fromthe industrial point of view.

The need was therefore felt to have available (per)fluorinated polymers,in particular based on PTFE, for the coating of metal surfaces, capableto form films having a low thickness from 0.3 to 10 micron, preferablyfrom 0.5 to 5 micron, still more preferably from 1 to 3 micron, with thefollowing combination of properties:

-   excellent adhesion properties;-   low friction coefficient;-   crack free;-   good wear resistance;-   good scratch resistance;-   no modification of the finishing degree of treated metal surfaces.

It has been surprisingly and unexpectedly found by the Applicant thatparticular PTFE dispersions, formed by surfactants and organic orinorganic compounds belonging to the sequestrant class, can be directlyapplied on metal surfaces without pre-treating the support by sandblastor etching, or mixing the fluoropolymer dispersion with hydrogenatedresins.

An object of the present invention is a composition based on PTFE,homopolymer or modified, comprising for 100 parts of the component 1)PTFE:

-   1) an aqueous nanodispersion, or latex, of said homopolymer or    modified PTFE, having a primary particle diameter from 5 to 100 nm,    preferably from 10 to 80 nm;-   2) from 3 to 45 parts by weight, preferably from 5 to 30 parts by    weight, of a surfactant or surfactant mixtures;-   3) from 0.2 to 20 parts by weight, preferably from 0.4 to 10 parts    by weight of an organic or inorganic sequestrant, capable to give    bi- or poly-coordination bands, which forms with metal ions soluble    complexes and prevents from forming insoluble salts of these metals;    and optionally:-   4) from 0 to 60 parts by weight, preferably from 0 to 50 parts by    weight of a solid lubricating compound, preferably selected from the    following:    -   sulphides and selenides of the transition elements belonging to        the groups VB and VIB of the Element Periodic Table, preferably        molybdenum and tungsten,    -   carbon compounds as graphite and C60 and C70 fullerenes.

The homopolimer or modified PTFE latex, containing particles with adiameter from 5 to 100 nm, can be obtained by radicaltetrafluoroethylene polymerization in the presence of a microemulsion asdescribed in EP 969,027 in the name of the Applicant, hereinincorporated by reference. The microemulsions used in polymerization aredescribed in U.S. Pat. No. 4,864,006 and U.S. Pat. No. 4,990,283.

The preferred nanoemulsions of the component 1) PTFE for thecompositions according to the present invention contain particles havingan average diameter from 10 to 80 nm, and are selected from thefollowing classes:

-   homopolymer PTFE nanoemulsions;-   modified PTFE nanoemulsions, i.e. TFE copolymers with one or more    comonomers, containing at least one unsaturation of ethylene type,    in an amount up to 6% molar, preferably up to 1% molar based on the    polymer.

The comonomers which can be used to prepare the modified PTFE of theaqueous dispersions component 1), are both of hydrogenated andfluorinated type. Among the hydrogenated comonomers it can be mentioned:ethylene, propylene, acrylic monomers, for example methyl(meth)acrylate,(meth)acrylic acid, butylacrylate, hydroxyethylhexylacrylate, styrenemonomers, such for example styrene.

Among the fluorinated comonomers it can be mentioned:

-   C₃-C₈ perfluoroolefins, for example hexafluoropropene (HFP);-   C₂-c₈ hydrogenated fluoroolefins, such as vinyl fluoride (VF),    vinylidene fluoride (VDF), trifluoroethylene, hexafluoroisobutene,    CH₂═CH—R_(f) perfluoroalkylethylene, wherein R_(f) is a C₁-C₆    perfluoroalkyl for example CF₃, C₂F₅, C₃F₇;-   C₂-C₈ chloro- and/or bromo- and/or iodo-fluoroolefins, for example    chlorotrifluoroethylene (CTFE);-   CF₂═CFOR^(A) _(f) (per)fluoroalkylvinylethers (PAVE), wherein R_(f)    is a C₁-C₆ (per)fluoroalkyl as above;-   CF₂═CFOX^(I) (per)fluoro-oxyalkylvinylethers, wherein X^(I) is a    C₁-C₁₂ alkyl, or a C₁-C₁₂ oxyalkyl, or a C₁-C₁₂    (per)-fluoro-oxyalkyl having one or more ether groups, for example    perfluoro-2-propoxy-propyl; fluorodioxoles, preferably    perfluorodioxoles.

Fluorinated comonomers are preferred, preferably those which do notcompromise the thermal PTFE stability, in particularperfluoromethoxydioxole (MDO), perflubropropylvinylether (PPVE),perfluoromethylvinylether (PMVE), perfluoroethylvinylether (PEVE) andperfluoropropene (PFP).

The surfactants component 2) can be anionic, cationic, non ionic and canbe hydrogenated or fluorinated. Mixtures of surfactants, both ionic andnonionic, hydrogenated and fluorinated can be used.

Among hydrogenated surfactants those non ionic can be mentioned obtainedby reaction of ethylenoxide (EO), which represents the hydrophilic part,with compounds capable to give to the structure an hydrophobiccharacter, such for example the following:

-   propylenoxide (polypropylenoxide);-   C₈-C₂₄ alcohols and aliphatic acids, both saturated and unsaturated;-   primary, secondary, tertiary alkylamines, wherein an alkyl is C₈-C₂₄    and the other substituents are hydrogen or C₁-C₅ linear or branched    alkyl;-   alkylphenols, wherein the alkyl is as defined for alkylamines;-   polycyclic hydrocarbons belonging to the terpene class, such for    example β-pinene.

The compound obtained from the above reaction contains a polyoxyethylenechain having from 8 to 24 EO units.

Among non ionic hydrogenated surfactants those having the followingstructure are preferred:

-   polyethoxylated alkylphenols having formula:    R^(II)—C₆H₄O—(CH₂CH₂)_(pI)—OH    wherein:    -   R^(II) is a saturated or unsaturated, linear or branched alkyl        chain having from 8 to 10 carbon atoms,    -   pI=8-12;-   etho-propoxylated alcohols having formula:    C_(nI)H_(2nI+1)(OC₃H₆O)_(mI)—(OCH₂CH₂)_(qI)OH    wherein:    -   nI=8-18, mI=0-30, qI=8-24;-   polyethoxylated alcohols having formula:    C_(nII)H_(2nII+1)(OCH₂CH₂)_(mII)OH    wherein:    -   nII=8-24, preferably 8-18,    -   mII=2-50, preferably 2-18.

Among anionic hydrogenated surfactants those having the followingformula can for example be mentioned:R^(I) _(A—M) ^(A)X^(A)wherein:

-   R^(I) _(A) is a C₈-C₁₈ aliphatic hydrocarbon radical, both saturated    and unsaturated, having a linear or branched chain, for example an    oleyl, stearyl, tridecyl, lauryl, decyl radical;-   M^(A) is an acid group such for example COO—, SO₃—;-   X^(A)=H, NH₄, Na, Li, K.

Among cationic hydrogenated surfactants, the tetraalkylammonium saltscan be mentioned wherein at least an alkyl is C₈-C₂₄ and the othersubstituents are hydrogen or C₁-C₅, linear or branched, alkyl.

Among anionic fluorinated surfactants those selected from the followingclasses can be mentioned:.T—O—R_(f)—CFX—COOM  (IA)wherein:

-   X=F, CF₃;-   M=H, NH₄, Na, Li, K;-   T is a C₁-C₃ (per)fluoroalkyl group, optionally containing one Cl    atom; preferably T is selected from the following: —CF₃, —C₂F₅,    —C₃F₇, —CF₂Cl, —C₂F₄Cl, —C₃F₆Cl; optionally one or two F atoms can    be substituted by H;-   R_(f) is a (per)fluoropolyoxyalkylene radical having a number    average molecular weight M_(n) in the range 200-2,000, preferably    350-1,000; R_(f) is in particular selected from the following    classes:-   (a) —(CF₂CF(CF₃)O)_(m)(CFXO)_(n)—    -   wherein m and n are integers such that the n/m ratio is in the        range 0.01-0.5 and the molecular weight is within the above        range;-   (b) —(CF₂CF₂O)_(p)(CF₂O)_(q)—    -   wherein p and q are integers such that the q/p ratio is in the        range 0.5-2 and the molecular weight is within the above range;-   (c) —(CF₂CF(CF₃)O)_(r)—(CF₂CF₂O)_(s)—(CFXO)_(t)—    -   wherein r, s and t are integers such that r+s is in the range        1-50, the t/(r+s) ratio is in the range 0.01-0.05, X is F, CF₃,        and the molecular weight is within the above range;-   (d) —(CF(CF₃)CF₂O)_(u)—    -   wherein u is an integer such that the molecular weight is within        the above range;-   (e) —(CYZ—CF₂CF₂O)_(v)—    -   wherein Y and Z, equal to or different from each other, are F,        Cl or H; v is an integer such that the molecular weight is        within the above range;-   (f) —(CF₂CF₂O)_(v)—    -   w is an integer such that the molecular weight is within the        above range.        CF₃(CF₂)_(nT)COOM  (IIA)        wherein nT can range from 4 to 12,        F—(CF₂—CF₂)_(nV)—CH₂—CH₂—SO₃M  (IIIA)        wherein M is as above and nV ranges from 2 to 5.

Among the formula (IA) compounds, as anionic surfactants, those havingthe following formulaT—O—(C₃F₆O)_(m)(CF₂O)_(n)—CF₂—COOMwherein T, M, m and n are as above, are preferred.

The non-ionic fluorinated surfactants are preferably selected from thefollowing:CF₃(CF₂)_(y)—L—R_(h)  (IB)wherein y is an integer from 3 to 20, L and R_(h) are as defined below;T—O—R_(f)—L—R_(h)  (IIB).wherein:

-   R_(f) is selected among the above structures (a), (b), (c), (d),    (e), (f);-   L is a divalent organic group, linking group between R_(f) and    R_(h), selected from —CO—NR¹—, —CH₂(OCH₂CHR²)_(a)—O—,    —CH₂(OCH₂CHR²)_(b)—O—CO—, —CH₂O—(CH₂)_(c)—CO—O—, —CH₂—CH₂—O—,    —CH₂—CH₂—;    wherein:    -   —R¹ is —H or a C₁-C₄ alkyl;    -   —R² is —H or a C₁-C₂ alkyl;    -   a, b are integers from 0 to 6, preferably from 0 to 2;    -   c is an integer from 1 to 3;        R_(h) is a radical having a polyoxyalkylene structure selected        from:-   (i) —(CH₂CH₂O)_(qI)CH₂CH₂Z_(u), wherein: qI is an integer from 5 to    70, preferably from 6 to 25; Z_(u) is selected from —OH, C₁-C₄    alkoxy;-   (ii) —(CH₂CH₂O)_(rI)(CH₂CH(CH₃)O)_(sI)CH₂CHR³Z_(u); wherein: rI+sI    is an integer from 5 to 70, preferably from 10 to 50; the rI/sI    ratio is in the range 0.1-10, preferably 0.5-5; R³ is selected    between —H and —CH₃; ZU is as above;-   T is as above.

Preferably the non ionic fluorinated surfactants are selected from thefollowing:

-   structure (IB) compounds wherein y=5, L=—CH₂—CH₂—O—,    R_(h)=—(CH₂CH₂O)_(qI)CH₂CH_(2l OH wherein qI=)6; said compounds are    marketed with the name FORAFAC 1110D®;-   structure (IIB) compounds, wherein R_(f) has structure (a),    T=—C₃F₆Cl, m and n such to give a molecular weight in the range    450-650; L=—CONH—; R_(h)=—(CH₂CH_(2l O)) _(qI)—CH₂CH₂OCH₃ wherein    qI=21, said compounds are marketed with the name Fluorolink C455®.

The organic or inorganic sequestrants (complexants) component 3) usablein the invention are capable to give bi- or poly-coordination bands andform with metal ions soluble complexes and prevent from forminginsoluble salts of said metals. Preferably the sequestrants have afunctionality of acid type, for example of carboxylic or phosphonictype, in a number higher than or equal to two, preferably two or four. Atest to verify if component 3) complies with the present inventionconditions is the following: to an aqueous solution at pH 10 containinga Ca²⁺ soluble salt, preferably calcium nitrate, in an amount equal to360 mg (as Ca²⁺), 1 g of the sequestrant is added, and subsequently awater-soluble salt of an anion, preferably carbonate, which precipitatesthe calcium as insoluble salt. When an insoluble salt forms, component3) is not suitable to be used in the present invention.

When the sequestrants are of inorganic type, they are for exampleselected from polyphosphates,. for example sodium hexamethaphosphateNa₆P₆O₁₈, potassium pyrophosphate K₄P₂O₇, sodium tripolyphosphateNa₅P₃O₁₀.

When the sequestrants are of organic type, they are for exampleamino-polycarboxylic acids such as EDTA, polyhydroxymonocarboxylic acidssuch as gluconic acid and phosphonates.

Among organic sequestrants the following are preferred:

-   (CH₂COOH)₂—N—CH₂—CH₂—N—(CH₂COOH)₂, ethylendiaminotetraacetic acid    (EDTA);-   (CH₂COOH)₂—N—CH₂—CH₂—N(CH₂COOH)(CH₂CH₂OH),    N-hydroxyethylethylendiaminotriacetic acid (HEDTA);-   N—(CH₂COOH)₃, nitrilotriacetic acid (NTA);-   CH₃—CH(H₂PO₃)₂, 1-hydroxyethyliden-1,1-diphosphonic acid (HEDP);-   N(CH₂—PO₃H₂)₃, aminotrimethylenphosphonic acid (ATMP);-   (H₂O₃P—CH₂)₂—N—CH₂—CH₂—N(H₂O₃P—CH₂)₂,    ethylendiaminotetramethylenphosphonic acid (EDTMP);-   (H₂O₃P—CH₂)₂—N—CH₂—CH₂—N(CH₂PO₃H₂)—CH₂—CH₂—N(H₂O₃P—CH₂)₂    diethylentriamino pentamethylenphosphonic acid (DTPMP);-   (H₂O₃P—CH₂)₂—N—(CH₂)₆—N(H₂O₃P—CH₂)₂,    hexamethylendiaminotetramethylenphosphonic acid (HMDTMP).

The optional component 4) is well known in the prior art and belongs tothe class of the compounds used to lower the friction coefficient.Preferably it is selected from the following: MoS₂, WS₂ and graphite.

The present invention compositions can optionally be further dilutedwith water, and added with adhesion promoters, for example colloidalsilica, rheological modifiers to regulate the viscosity, for examplewater-soluble polymers.

Before applying the invention compositions, the metal or steelsubstratum to be treated can optionally be pretreated withfunctionalized perfluoropolyethers. Preferably the perfluoropolyethersare mono or bifunctional. Still more preferably the end groups are ionicand of phosphate type. It has been found by the Applicant that thethicknesses of said functionalized perfluoropolyethers on the metalsurface or steel can also be very thin, even at a monomolecular level.

The preferred mono- or diphosphate perfluoropolyethers have thefollowing formula:R^(B) _(f)—[CF₂CH₂—O—L^(B)—P(O)(OZ₁)(OZ₂)]₁  (I)wherein 1=1 or 2;

-   L^(B) is a bivalent linking group, preferably of the type    (CHR₁CHR₂O)_(n″)wherein R₁, R₂ equal to or different from each    other, are selected between H. CH₃; n″ is an integer in the range    1-50, preferably 1-6;-   Z₁ equal to or different from Z₂ selected from H, alkaline or    ammonium cation, di- or tri-alkanolammonium cation wherein the    alkanol comprises from 1 to 20 C atoms, preferably 1-4 C atoms, di-    or tri- or tetra-alkylammonium cation wherein the alkyl comprises    from 1 to 20 C atoms, preferably 1-4 C atoms, or R_(f)—CF₂CH₂—O—L—;-   R^(B) _(f) represents a (per)fluoropolyether chain having number    average molecular weight comprised between about 400 and about    1,800, preferably from 500 to 1,300, said (per)fluoropolyether chain    comprising repeating units selected from one or more of the    following:    -   a) —(C₃F₆O)—;    -   b) —(CF₂CF₂O)—;    -   c) —(CFXO)—, wherein X=—F, —CF₃;    -   d) —CF₂(CF₂)_(z), CF₂O—, wherein z′ is an integer 1 or 2;    -   e) —CH₂CF₂CF₂O—.

When R^(B) _(f) is monofunctional (1=1), one end group is of theperfluoroalkyl type such for example CF₃O, C₂F₅O, C₃F₇O; optionally inthe perfluoroalkyl end groups one fluorine atom can be substituted byone chlorine or hydrogen atom; examples of said fluoroalkyl end groupsare ClC₃F₆O, HC₃F₆O;

when R^(B) _(f) is of the bifunctional (per)fluoropolyether type and ithas preferably one of the following structures:

-   1) —(CF₂O)_(a′)—(CF₂CF₂O)_(b′)— with b′/a′ comprised between 0.3 and    10, extremes included, a′ and b′ being integers and a′ different    from 0;-   2) —(CF₂—(CF₂), —CF₂O)_(b′)— wherein z′ is an integer equal to 1 or    2;-   3) —(C₃F₆O)_(r′)—(C₂F₄O)_(b′)—(CFXO)_(t′)— with r′I/b′=0.5-2.0    (r′+b′)/t′=10-30, b′ and t′ being different from 0;-   4) —(OC₃F₆)_(r′)—(CFXO)_(t′)—OCF₂—R^(B′)    _(f)—C₂O—(C₃F₆O)_(r′)—(CFXO)_(t′)—;-   5) —(CF₂CF₂CH₂O)_(q)—R^(B) _(f)—O—(CH₂CF₂CF₂O)_(q′)—    wherein:    -   R^(B′) _(f) is a fluoroalkylene group from 1 to 4 carbon atoms;    -   r′, t′, q′ are integers, X=F, CF₃;-   6) —(C₃F₆O)_(r′)—OCF₂—R^(B′) _(f)—CF₂O—(C₃F₆O)_(r′)—    wherein in said formulas:-   —(C₃F₆O)—can represent units of formula:    -   —(CF(CF₃)CF₂O)— and/or —(CF₂—CF(CF₃)O)—-   a′, b′, q′, r′, t′, are integers, the sum of which is such that    R^(B′) _(f) shows number average molecular weight M_(n) values    comprised between about 400 and about 1,800, preferably between 500    and 1,500.

The preferred (per)fluoropolyether chain R^(B) _(f) is selected from thefollowing structures:

-   from those bifunctional (1=2):    -   —(CF₂O)_(a′)—(CF₂CF₂O)_(b′)—;    -   —(C₃F₆O)_(r′)—(C₂F₄O)_(b′)—(CFXO)_(t′)—;-   from those monofunctional (1=1):    -   —(C₃F₆O)_(r′)—(CFLOO)_(t′)—;-   wherein X and the indexes a′, b′, r′, t′ have the above value, still    more preferably —(CF₂O)_(a′)—(CF₂CF₂O)_(b′)—, wherein the indexes a′    and b′ have the above values.

The preferred compounds of formula (I) are those whereinL^(B)=(CH₂—CH₂O)_(n″) with n″ integer from 1 to 3; Z₁ equal to ordifferent from Z₂ is selected from H, NH₄, or an alkaline metal cation;1=2.

The (per)fluoropolyethers of general formula (I) are obtainable by thewell known processes of the prior art, see for example the followingpatents, herein incorporated by reference: U.S. Pat. No. 3,665,041, U.S.Pat. No. 2,242,218, U.S. Pat. No. 3,715,378, EP 239,123, EP 1,145,722.

The invention compositions are applied on metals, steels, withconventional methods such as casting, spraying, glazing, spin coating,deep coating also without pretreating the metal surface. For example byusing the spin coating, a constant spinning rate in the range2,000-5,000 rpm is preferably used; the time is generally comprisedbetween 30 seconds and 5 minutes.

After the application on the metal surface the obtained film is sinteredat a temperature higher than 320° C., preferably in the range 390°C.-410° C.; subsequently the sintered film is cooled by air exposure.

As said, the present invention compositions show the excellentcombination of the above properties.

The films obtained by applying to metal substrata the compositionsaccording to the present invention show an excellent adhesion to thesupport. This is surprising and unexpected on the basis of the prior artsince tests carried out by the Applicant on compositions having the samecomposition as those of the present invention, but using a latex whereinthe PTFE particles have sizes higher than those of the present inventioncomponent 1), give films which substantially do not adhere to metalsupports. See the Examples.

The following aspects of the compositions according to the presentinvention result, on the basis of the prior art, quite unexpected:

-   the fact that the addition of sequestrants made it possible to    improve the scratch, i.e. to improve the adhesion to the film metal    support and its mechanical resistance;-   the fact, that the addition of the optional solid lubricants, for    example molybdenum sulphide, in combination with sequestrants made    it possible to improve further the wear resistance and the adhesion    to the support (improved scratch).

The following Examples are given for illustrative purposes, but they arenot limitative of the scope of the invention.

EXAMPLES

Characterization:

Particle Diameter

The particle diameter is measured by a laser light scatteringinstrument, in particular Photon Correlation Spectroscopy, equipped withBrookhaven correlator model 2030 AT and with an argon laser light sourceat a wave length of 514.5 nm by Spectra-Physics. The latex samples to beevaluated are previously diluted with water filtered at 0.2 μm onMillipore filter until the instrument signal is not within the scale.The scattering measure is carried out at room temperature (20° C.-25°C.) at a 90° angle. The latex particle diameter is obtained by thecumulant method.

Polymer Content in the Latex

About 3 grams of latex are weighed in a glass beaker and put in a stoveto dry for 2 hours at 105° C. and then sintered at 380° C. for 15minutes. The content of dry product of the latex is obtained from theformula:dry product %=100×weight after sintering/latex initial weight.Surfactant Content in the Latex

The difference between the solid weight after drying at 105° C. and thefinal weight after sintering gives the amount of the present surfactant.

First Melting Temperature Determination

The first melting temperature determination is carried out by thedifferential calorimetry technique by using a Perkin Elmer calorimeterof the DSC 7 type. About 10 mg of the dried polymer are heated from thetemperature of 220° C. up to the temperature of 370° C. at a rate of 10°C./min. The temperature corresponding to the peak of the meltingendothermic curve is indicated as the first melting temperature of thepolymer.

Wetting Capability

The wetting capability of the formed latex, after application on thesubstratum (aluminum, copper, steel, stainless steel sheets), isvisually evaluated by observing the behaviour of the film spread bycasting on the substratum. The wetting capability is consideredsufficient when the homogeneous substratum covering, without defects isobtained. The wetting capability is considered insufficient when“islands” of unwet substratum are formed.

Film Thickness Determination

The film thickness is measured according to ASTM B 499.

Presence Determination of Cracks in the Film

The crack presence is noticed by examining the film by a 40magnification optical microscope.

Film Adhesion to the Substratum

The adhesion is evaluated with the following alternative methods:

-   cross cut method (ASTM D 3359-87);-   one scratches the film with a steel spherical point having a    diameter of 0.4 mm, with an applied load of 600 g, and one observes    at the 40 magnification optical microscope:    -   a) if the film surface shows a crack with detachment, with        formation of a “V” crack;    -   b) or if the film gets scratched without detaching itself from        the substratum.

The specimen passes the test if the film remains adherent to thesubstratum (case b)).

Film Scratch Resistance

The film scratch resistance is measured by observing with a reflectingoptical microscope the scratch behaviour of the film adhering to thesubstratum. The test is an index of the film adhesion to the substratumand of the film mechanical resistance. The substratum covered by thepolymer film is observed at the 40 magnification stereo microscope. Witha steel spherical point having a diameter of 0.4 mm, with an appliedload of 100 g, the surface is cut with circular trajectory countingabout 5 rotatory movements (cycles) on a film surface having 2×2 mmsizes.

The film specimen is evaluated as follows:

-   if the film remains integral for the whole test, the scratch    resistance is put equal to 3;-   if the film is cut between the third and fourth cycle, the scratch    resistance is put equal to 2;-   if the film is cut by the spherical point during the first 2 cycles,    the scratch resistance is put equal to 1.    Friction Coefficient

The friction coefficient is measured by the ASTM D 1894 method.

Resistance of the Film to Wear

To the specimen a steel spherical point having a diameter of 0.95 mm isapplied with a load of 50 or 100 g. The point is let drag on the film ata rate of 800 mm/min. By using a 40 magnification optical microscope onenotices if at the edges of the incision groove, shavings of removedmaterial are present. The presence of shavings shows that the film inthe test conditions is subject to wear.

By the microscope, using a millesimal comparator, one determines thegroove width, which is taken as film hardness index.

Example 1 Polymerization of a Homopolymer PTFE Nanoemulsion

In a glass reactor there are introduced:

-   5 parts of an anionic perfluorinated surfactant having structure    (IA):    ClC₃F₆O(C₃F₆O)_(n)CF₂COONH₄  (IA)    wherein n is such that the acidimetrical molecular weight is equal    to 530;-   3 parts of α-perfluoropolyether having structure:    R_(f)O(C₃F₆O)_(n)(CF₂O)_(m)R′_(f)    wherein n and m are integers such to give a number average molecular    weight of about 700; R_(f), R′_(f), equal to or differnt from each    other are perfluoroalkyls from 1 to 3 carbon atoms;-   8 parts of water.

The resulting microemulsion results perfectly limpid.

3810 grams of the obtained microemulsion are added to 29 litres ofcarefully degassed water into a 50 litre autoclave equipped with amechanical stirrer and previously put under vacuum. Also 140 grams ofparaffin with softening point in the range 52° C.-54° C. had beenpreviously introduced into the reactor. 900 mbar (9.10⁴ Pa) of ethaneare fed to the autoclave. The autoclave is kept under mechanicalstirring and is pressurized with tetrafluoroethylene (TFE) up to apressure of 20 bar (2 MPa) at a temperature of 88° C. At this point 500cc of solution of (NH₄)₂S₂O₈ (APS) corresponding to 5,000 mg of APS arefed to the autoclave as polymerization initiator.

When the pressure in the reactor has decreased of 0.5 bar (5.10⁴ Pa),one starts to feed TFE by means of a compressor so as to maintain aconstant pressure of 20 bar inside the reactor. In the meantime thereactor internal temperature is increased up to 100° C. at a rate equalto 0.7° C./min. After 32 minutes, the TFE feeding is stopped, thereactor evacuated and cooled.

The polymer primary particle diameter measured by Laser Light Scattering(LLS) is equal to 17 nm. The discharged latex has a concentration of 312g PTFE/kg dispersion. The PTFE latex contains a concentration by weightof anionic perfluorinated surfactant equal to 8.65% based on the PTFE.

By the DSC analysis it results that the obtained polymer has a firstmelting temperature of 323.6° C.

To 10 kg of said dispersion, put in a thermostatable Pyrex glassreactor, 6 kg of a solution at 25% by weight of Triton X-100 are added.The mixture, initially at room temperature, is carefully homogenized andthe temperature increased up to 71° C. At this temperature stirring isstopped and an upper clear aqueous phase and a lower phase having a highcontent of fluorinated polymer particles separate. The lower phasecontains an amount of fluorinated polymer equal to 43% by weight and ofTriton X-100 equal to 6.4% by weight.

Example 1A Preparation of a Film According to the Invention byFormulating the Polymerization Latex of Example 1 with a SequestrantAdditive (Diphosphonate Potassium Salt) using a not Pretreated SteelPlate

To prepare the film the latex is formed as follows (percentages byweight referred to the weight of the total dispersion): PTFE   20%Triton X-100   4% Ammonium perfluorooctanoate (PFOA)   1% Potassium saltof the hydroxyethyliden- 0.15% 1,1-diphosphonic acid (Sequion ® 10K44)

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table I.

Example 2 Polymerization of a Modified PTFE Nanoemulsion

1503 grams of the microemulsion obtained as in Example 1 are added to 29litres of carefully degassed water in a 50 litre autoclave equipped witha mechanical stirrer and previously put under vacuum. Also 210 grams ofparaffin with softening point in the range 52° C.-54° C. had beenpreviously introduced into the reactor. 125 grams ofperfluoromethylvinylether (MVE) are fed to the autoclave. The autoclaveis kept under mechanical stirring and is pressurized withtetrafluoroethylene (TFE) up to a pressure of 20 bar (2.10⁶ Pa) at atemperature of 80° C. At this point 85 ml of solution of (NH₄)₂S₂O₈(APS) corresponding to 850 mg of APS are fed to the autoclave aspolymerization initiator.

When the pressure in the reactor has decreased of 0.5 bar (5.10⁴ Pa),one starts to feed TFE by means of a compressor so as to maintain aconstant pressure of 20 bar inside the reactor. In the meantime thereactor internal temperature is increased up to 85° C. with a gradientof 0.25° C./min. After 120 minutes, the TFE feeding is stopped, thereactor evacuated and cooled.

The polymer primary particle diameter measured by Laser Light Scattering(LLS) results equal to 72 nm. The discharged latex has a concentrationof 330 g PTFE/kg dispersion. The modified PTFE latex contains aconcentration by weight of anionic perfluorinated surfactant equal to3.16% based on the PTFE.

To 10 kg of this dispersion, put in a thermostatable Pyrex glassreactor, 6 kg of a solution at 25% by weight of Triton X-100 are added.The mixture, initially at room temperature, is carefully homogenized andthe temperature increased up to 70° C. At this temperature stirring isstopped and an upper clear aqueous phase and a lower phase having a highcontent of fluorinated polymer particles separate. The lower phasecontains an amount of fluorinated polymer equal to 49.3% by weight andof Triton X-100 equal to 7.3% by weight.

By the DSC analysis it results that the obtained polymer has a firstmelting temperature of 321.6° C. By the TGA analysis it is determined aweight loss of 0.98% by weight at 425° C. in 2 hours, which is an indexof good thermal stability.

Example 2A Preparation of a Film According to the Invention byFormulating the Polymerization Latex of Example 2 with a SequestrantAdditive (diphosphonate potassium salt) and Application on the SteelPlate Treated with PFPE phosphate

The latex obtained in Example 2 is formed as follows

-   Modified PTFE 30%-   Triton X-100 4%-   Potassium salt of the hydroxyethyliden-1,1-diphosphonic acid    (Sequion® 10K44) 0.15%

The substratum (steel plate) is previously treated with anhydroalcoholic emulsion (water/isopropyl alcohol 20/80) at 2% by weightof Fluorolinko F10 under the form of ammonium salt, chemically definedas a bifunctional PFPE phosphate, having number average molecular weightof about 1,500, corresponding to the following formula:Q—CH₂CF₂—O—(CF₂ ⁰)_(a)—(CF₂CF₂O)_(b)—CF₂CH₂—Qwherein:

-   Q=—(OCH₂CH₂)_(n″)—O—P(O)(O⁻NH₄ ⁺)₂-   n″, a and b being such as to give the indicated molecular weight.

The hydroalcoholic emulsion is spread on the plate, which is then driedat 60° C. After drying the possible compound excess is removed forexample by hand, by rubbing with a cloth.

The so formed latex is deposited by casting, with a slope of 400-500, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table I.

Example 3 (Comparative) Polymerization of a Homopolymer PTFE Emulsion

11 grams of the aqueous solution of ammonium perfluorooctanoate and 31litres of carefully degassed water are fed to a 50 litre autoclaveequipped with a mechanical stirrer and previously put under vacuum. Also140 grams of paraffin with softening point in the range 52° C.-54° C.had been previously introduced into the reactor. The autoclave is keptunder mechanical stirring and is pressurized with tetrafluoroethylene(TFE) up to a pressure of 20 bar (2.10⁶ Pa) at a temperature of 62° C.Successively 500 ml of a solution of (NH₄)₂S₂O₈ (APS) and disuccinicperoxide (DSAP) corresponding to 150 mg of APS and 3,000 mg of DSAP arefed.

When the pressure in the reactor has decreased of 0.5 bar (5.10⁴ Pa),one starts to feed TFE by means of a compressor so as to maintain aconstant pressure of 20 bar inside the reactor. In the meantime thereactor internal temperature is increased up to 80° C. at a rate equalto 0.5° C./min. During the reaction 50.5 grams of the aqueous solutionat 100 grams/litre of ammonium perfluorooctanoate (PFOA) are fed to theautoclave. After 90 minutes, the TFE feeding is stopped, when 15,800grams of TFE have reacted, the reactor is vented and cooled. The latexdischarged from the reactor has a concentration of 510 g PTFE/litre ofwater.

The polymer primary particle diameter measured by Laser Light Scattering(LLS) is equal to 230 nm. The obtained PTFE latex is concentrated up toa PTFE concentration equal to 60% by weight. The PTFE latex contains aconcentration by weight of anionic perfluorinated surfactant PFOA equalto 0.08% b<sfd on the PTFE.

To 10 kg of this dispersion, put in a thermostatable Pyrex glassreactor, 2 kg of a solution at 25% by weight of Triton X-100 are added.The mixture, initially at room temperature, is carefully homogenized andthe temperature increased up to 69° C. At this temperature stirring isstopped and an upper clear aqueous phase and a lower phase having a highcontent of fluorinated polymer particles separate. The lower phasecontains an amount of fluorinated polymer equal to 66% by weight and ofTriton X-100 equal to 1.49% by weight.

The DSC analysis shows that the polymer has a first melting temperatureof 343° C.

Example 4 Preparation of a Film According to the Invention using theComposition of Example 1A by Application on a Steel Plate treated withFluorolink® F10

The substratum (steel plate) is previously treated with Fluorolink® F10as described in Example 2A.

The latex formed as in Example 1A is deposited by casting, with a slopeof 40°-50°, on a steel plate previously treated in an oven at 400° C.for 20 minutes. Then it is dried at 120° C. in a ventilated stove andthe so formed film is treated in an oven at 400° C. for 4 min. to allowthe polymer sintering. The characterization is reported in Table I.

Example 5 Preparation of a Film According to the Invention using a notPretreated Steel Plate, adding to the Composition of Example 1A a SolidLubricant (molybdenum sulphide)

To prepare the film the latex is formed as follows (percentages byweight referred to the weight of the total dispersion): PTFE   20%Triton X-100   4% PFOA   1% Potassium salt of the hydroxyethyliden-0.15% 1,1-diphosphonic acid (Sequion ® 10K44) Molybdenum sulphide   4%

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table I.

Example 6 Preparation of a Film According to the Invention using a notPretreated Steel Plate, by adding to the Composition of Example 2A aSolid Lubricant (molybdenum sulphide)

To prepare the film the latex is formed by omitting the surfactant PFOA,as follows (percentages by weight referred to the weight of the totaldispersion): Modified PTFE   20% Triton X-100   4% Potassium salt of thehydroxyethyliden- 0.15% 1,1-diphosphonic acid (Sequion ® 10K44)Molybdenum sulphide   4%

The so formed latex is deposited by casting, with a slope of 40° -50°,on a steel plate previously treated in an oven at 400° C. for 20minutes. Then it is dried at 120° C. in a ventilated stove and the soformed film is treated in an oven at 400° C. for 4 min. to allow thepolymer sintering. The characterization is reported in Table I.

Example 7 Preparation of a Film According to the Invention by Applyingthe Composition of Example 1A on a not Pretreated Aluminum Plate

Example 1A is repeated but by applying the latex to a not pretreatedplate of aluminum at the place of steel. The characterization isreported in Table I.

Example 8 Preparation of a Film According to the Invention by Applyingthe Composition of Example 1A on a not Pretreated Copper Plate

Example 1A is repeated but by applying the latex to a not pretreatedplate of copper at the place of steel. The characterization is reportedin Table I.

Example 9 Preparation of a Film by Using a not Pretreated Steel PlateAccording to the Invention by Forming the Polymerization Latex ofExample 1 with a Sequestrant Additive

To prepare the film the latex is formed as follows (percentages byweight referred to the. ′weight of the total dispersion): PTFE   20%Triton X-100   4% Ammonium perfluorooctanoate (PFOA)   1%Ethylendiaminotetraacetic acid 0.15% disodic salt

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table I.

Example 10 (Comparative) Preparation of a Film by Using a not PretreatedSteel Plate, Starting from a Composition as in Example 1A but Withoutthe Sequestrant Additive

For the application (film preparation) the latex is formed as follows(percentages by weight referred to the weight of the total dispersion):PTFE 20% Triton X-100  4% PFOA  1%

The so prepared latex is deposited by casting, with a slope of 40°-50°,on a steel plate previously treated in an oven at 400° C. for 20minutes. Then it is dried at 120° C. in a ventilated stove and the soformed film is treated in an oven at 400° C. for 4 min. to allow thepolymer sintering. The characterization is reported in Table II.

Example 11 (Comparative) Preparation of a Film by Using a not PretreatedSteel Plate, Starting from a Composition as in Example 2A but Withoutthe Sequestrant Additive

The latex obtained in Example 2 is formed as follows: Modified PTFE 30%Triton X-100  4%

The so prepared latex is deposited by casting, with a slope of 40°-50°,on a steel plate previously treated in an oven at 400° C. for 20minutes. Then it is dried at 120° C. in a ventilated stove and the soformed film is treated in an oven at 400° C. for 4 min. to allow thepolymer sintering. The characterization is reported in Table II.

Example 12 (Comparative) Preparation of a film by Using a not PretreatedSteel Plate, by Forming the Polymerization Latex of Example 3 (EmulsionPolymerization) with a Sequestrant Additive (diphosphonate potassiumsalt)

To prepare the film the latex is formed as follows (percentages byweight referred to the weight of the total dispersion): PTFE   20%Triton X-100   3% Ammonium perfluorooctanoate (PFOA)   1% Potassium saltof the hydroxyethyliden- 0.15% 1,1-diphosphonic acid (Sequion ® 10K44)

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table II.

Example 13 (Comparative) Preparation of a Film by Using a not PretreatedSteel Plate Starting from a Mixture of the Latexes Obtained Respectivelyin the Example 3 (Comparative) and in Example 2 by Adding a SequestrantAdditive (diphosphonate potassium salt)

The latex mixture is prepared using an amount of the latex of Example 3(Comparative) and respectively of Example 2 such that the ratio betweenthe PTFE from emulsion polymerization and the modified PTFE frommicroemulsion polymerization is 95:5 by weight based on the solid.

To prepare the film the latex mixture is formed as follows (percentagesby weight referred to the weight of the total dispersion): PTFE + mod.PTFE   60% Triton X-100  3.5% Potassium salt of the hydroxyethyliden-0.15% 1,1-diphosphonic acid (Sequion ® 10K44)

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table II.

Example 14 (Comparative) Preparation of a Film According to theInvention, by Using a not Pretreated Steel Plate, by Forming the Latexof Example 1A with a Filler (titanium dioxide)

To prepare the film the latex is formed as follows (percentages byweight referred to the weight of the total dispersion): PTFE   20%Triton X-100   4% PFOA   1% Potassium salt of the hydroxyethyliden-0.15% 1,1-diphosphonic acid (Sequion ® 10K44) Titanium dioxide   10%

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table II.

Example 15 (Comparative) Preparation of a Film by Using a not PretreatedSteel Plate by Forming the Latex of Example 2A with a Solid Lubricant

To prepare the film the latex is formed by omitting the PFOA surfactant,as follows (percentages by weight referred to the weight of the totaldispersion): Modified. PTFE 20% Triton X-100  4% Molybdenum sulphide  4%

The so formed latex is deposited by casting, with a slope of 40°-50°, ona steel plate previously treated in an oven at 400° C. for 20 minutes.Then it is dried at 120° C. in a ventilated stove and the so formed filmis treated in an oven at 400° C. for 4 min. to allow the polymersintering. The characterization is reported in Table II. TABLE I WearIncision width Latex Thickness Adhesion Friction Load Load Shavings Ex.Support ex. μm Cracks Microsc. ASTM Scratch coeff. 50 g 100 g present 1Asteel 1 1 ÷ 2 — yes 5B 2 0.12 92 120 yes 2A steel 2 1 ÷ 2 — yes 3B 20.12 102 118 no 4 steel 1 1 ÷ 2 — yes 5B 2 0.11 118 141 yes 5 steel 1 1÷ 2 — yes 5B 3 0.11 40 64 no 6 steel 2 1 ÷ 2 — yes 5B 3 0.10 45 50 no 7alum. 1 3 — yes 5B 2 0.12 80 120 no 8 copper 9 steel 1 1 ÷ 2 — yes 5B 20.12 65 115 yes

TABLE II Wear Incision width Latex Thickness Adhesion Friction Load LoadShavings Ex. Support ex. μm Cracks Microsc. ASTM Scratch coeff. 50 g 100g present 10 steel 1 1 ÷ 2 — yes 5B 1 0.10 86 100 yes comp 11 steel 2 1÷ 2 — yes 4B 1 0.11 85  95 yes comp 12 steel 3 4 — no 0B — — — — — comp13 steel 3 + 2 — yes no 0B — — — — — comp 14 steel 1 1 ÷ 2 — yes 3B 10.20 120  130 yes comp 15 steel 2 1 ÷ 2 — yes 3B 1 0.12 80  90 no comp

1. Compositions based on PTFE, homopolymer or modified, comprising for100 parts of the component 1) PTFE: 1) an aqueous nanodispersion, orlatex, of said homopolymer or modified PTFE, having a primary particlediameter from 5 to 100 nm; 2) from 3 to 45 parts by weight of asurfactant or surfactant mixtures; 3) from 0.2 to 20 parts by weight ofan organic or inorganic sequestrant capable to give bi- orpoly-coordination bands, which forms with metal ions soluble complexesand prevents from forming insoluble salts of said metals; andoptionally: 4) from 0 to 60 parts by weight of a solid lubricatingcompound.
 2. Compositions according to claim 1, wherein thenanoemulsions of the component 1) PTFE are selected from the followingclasses: homopolymer PTFE nanoemulsions; modified PTFE nanoemulsions,i.e. TFE copolymers with one or more comonomers, containing at least oneunsaturation of ethylene type, in an amount up to 6% molar based on thepolymer.
 3. Compositions according to claim 2, wherein the comonomersused to prepare the modified PTFE of the aqueous dispersions component1), are both of hydrogenated and fluorinated type.
 4. Compositionsaccording to claim 3, wherein the hydrogenated comonomers are selectedfrom the following: ethylene, propylene, acrylic monomers, selected frommethyl(meth)acrylate, (meth)acrylic acid, butylacrylate,hydroxyethylhexylacrylate, styrene monomers.
 5. Compositions accordingto claim 3, wherein the fluorinated comonomers are selected from: C₃-C₈perfluoroolefins; C₂-C₈ hydrogenated fluoroolefins CH_(2═CH—R) _(f)perfluoroalkylethylene, wherein R_(f) is a C₁-C₆ perfluoroalkyl; C₂-C₈chloro- and/or bromo- and/or iodo-fluoroolefins; CF₂═CFOR^(A) _(f)(perfluoroalkylvinylethers (PAVE), wherein R_(f) is a C₁-C₆(per)fluoroalkyl as above; CF₂=CFOX^(I) (per)fluoro-oxyalkylvinylethers,wherein X^(I) is a C₁-C₁₂ alkyl, or a C₁-C₁₂ oxyalkyl, or a C₁-C₁₂(per)fluoro-oxyalkyl having one or more ether groups fluorodioxoles. 6.Compositions according to claim 5, wherein the comonomers are selectedfrom perfluoromethoxydioxoles (MDO), perfluoropropylvinylether (PPVE),perfluoromethylvinylether (PMVE), perfluoroethylvinylether (PEVE) andperfluoropropene (PFP).
 7. Compositions according to claim 1, whereinthe surfactants component 2) are anionic, cationic, non ionic,hydrogenated or fluorinated.
 8. Compositions according to claim 7,wherein the non-ionic hydrogenated surfactants are obtained by reactionof ethylenoxide (EO) with the following compounds: propylenoxide(polypropylenoxide); C₈-C₂₄ alcohols and aliphatic acids, both saturatedand unsaturated; primary, secondary, tertiary alkylamines wherein analkyl is C₈-C₂₄ and the other substituents are hydrogen or C₁-C₅ linearor branched alkyl; alkylphenols, wherein the alkyl is as defined foralkylamines; polycyclic hydrocarbons belonging to the terpene class. 9.Compositions according to claim 8, wherein the non-ionic hydrogenatedsurfactants are selected from the following: polyethoxylatedalkylphenols having formula:R^(II)—C₆H₄O—(CH₂CH₂)_(pI)—OH wherein: R^(II) is a saturated orunsaturated, linear or branched alkyl chain having from 8 to 10 carbonatoms, pI=8-12; etho-propoxylated alcohols having formula:C_(nI)H_(2nI+1)(OC₃H₆O)_(mI)—(OCH₂CH₂)_(qI)OH wherein: nI=8-18, mI=0-30,qI=8-24 polyethoxylated alcohols having formula:C_(nII)H_(2nII+1)(OCH₂CH₂)_(mII)OH wherein NII=8-24, mII=2-50. 10.Compositions according to claim 7, wherein the anionic hydrogenatedsurfactants are selected from those having the following formula:R^(I) _(A)—M^(A)X^(A) wherein: R^(I) _(A) is a C₈-C₁₈ aliphatichydrocarbon radical, both saturated and unsaturated, having a linear orbranched chain; M^(A) is an acid group; X^(A)=H, NH₄, Na, Li, K. 11.Compositions according to claim 7, wherein the cationic hydrogenatedsurfactants are the tetraalkylammonium salts wherein at least an alkylis C₈-C₂₄ and the other substituents are hydrogen or C₁-C₅, linear orbranched, alkyl.
 12. Compositions according to claim 7, wherein theanionic fluorinated surfactants are selected from the following:T—O—R_(I)—CFX—COOM  (IA) wherein: X=F, CF₃; M=H, NH₄, Na, Li, K; T is aC₁-C₃ (per)fluoroalkyl group, optionally containing one Cl atom;optionally one or two F atoms can be substituted by H; R_(f) is a(per)fluoropolyoxyalkylene radical having a number average molecularweight M, in the range 200-2,000; R_(f) is selected in particular fromthe following classes: (a) —(CF₂CF(CF₃)O)_(m)(CFXO)_(n), wherein m and nare integers such that the n/m ratio is in the range 0.01-0.5 and themolecular weight is within the above range; (b)—(CF₂CF₂O)_(p)(CF₂O)_(q)— wherein p and q are integers such that the q/pratio is in the range 0.5-2 and the molecular weight is within the aboverange; (c) —(CF₂CF(CF₃)O)_(r)—(CF₂CF₂O)_(s)—(CFXO)_(t)— wherein r, s,and t are integers such that r+s is in the range 1-50, the t/(r+s) ratiois in the range 0.01-0.05, X is F, CF₃, and the molecular weight iswithin the above range; (d) —(CF(CF₃)CF₂O)_(u)— wherein u is an integersuch that the molecular weight is within the above range; (e)—(CYZ—CF₂CF₂O)_(v)— wherein Y and Z, equal to or different from eachother, are F, Cl or H; v is an integer such that the molecular weight iswithin the above range; (f) —(CF₂CF₂O)_(w)— w is an integer such thatthe molecular weight is within the above range;CF₃(CF₂)_(nT)COOM  (IIA) wherein nT can range from 4 to 12,F—(CF₂—CF₂)_(nV)—CH₂—CH₂—SO₃M  (IIIA) wherein M is as above and nVranges from 2 to
 5. 13. Compositions according to claim 12, wherein theanionic surfactants of formula (IA) are selected from the following:T—O—(C₃F₆O)_(m)(CF₂O)_(n)—CF₂—COOM wherein T, M, m, and n are as above.14. Compositions according to claim 7, wherein the non-ionic fluorinatedsurfactants are selected from the following:CF₃(CF₂)_(y)—L—R_(h)  (IB) wherein y is an integer from 3 to 20, L andR_(h) are as defined below;T—O—R_(f)—L—R_(h)  (IIB) wherein; R_(f) is selected among the abovestructures (a), (b), (c), (d), (e), (f); L is a divalent organic group,linking group between R_(f) and R_(h), selected from —CO—NR¹, or—CH₂(OCH₂CHR²)_(a)—O—, —CH₂(OCH₂CHR²)_(b)—O—CO—, —CH₂O—(CH₂)_(c)—CO—O—,—CH₂—CH₂—O—, —CH₂—CH₂—; wherein: R¹ is —H or a C₁-C₄ alkyl; R² is —H ora C₁-C₂ alkyl; a, b are integers from 0 to 6; c is an integer from 1 to3; R_(h) is a radical having a polyoxyalkylene structure selected from:(i) —(CH₂CH₂O)_(qI)CH₂CH₂Z_(u), wherein: qI is an integer from 5 to 70;Z_(u) is selected between —OH, C₁-C₄ alkoxy; (ii)—(CH₂CH₂O)_(rI)(CH₂CH(CH₃)O)_(sI)CH₂CHR³Z_(u), wherein: rI+sI is aninteger from 5 to 70; the rI/sI ratio is in the range 0.1-10; R³ isselected between —H and —CH₃; Z_(u) is as above; T is as above. 15.Compositions according to claim 14, wherein the non-ionic fluorinatedsurfactants are selected from the following: structure (IB) compounds,wherein y=5, L=—CH₂—CH₂—O—, R_(h)=—(CH₂CH₂O)_(qI)CH₂CH₂OH wherein qI=6;structure (IIB) compounds, wherein R_(f) has structure (a), T=—C₃F₆Cl, mand n such to give a molecular weight in the range 450-650; L=—CONH—;R_(h)=—(CH₂CH₂O)_(qI)—CH₂CH₂OCH₃ wherein qI=21.
 16. Compositionsaccording to claim 1, wherein the organic or inorganic sequestrants havea functionality of acid type, selected between carboxilic or phosphonictype, in a number higher than or equal to two.
 17. Compositionsaccording to claim 16, wherein the inorganic sequestrants are selectedfrom polyphosphates, potassium pyrophosphate K₄P₂O₇, sodiumtripolyphosphate Na₅P₃O₁₀; those organic are selected from the groupcomprising amino-poly-carboxylic acids, polyhydroxymonocarboxylic acids,and phosphonates.
 18. Compositions according to claim 16, wherein thesequestrants are selected from the following:(CH₂COOH)₂—N—CH₂—CH₂—N—(CH₂COOH)₂, ethylendiaminotetraacetic acid(EDTA); (CH₂COOH)₂—N—CH₂—CH₂—N(CH₂COOH)(CH₂CH₂OH),N-hydroxyethylethylendiaminotriacetic acid (HEDTA); N—(CH₂COOH)₃,nitrilotriacetic acid (NTA); CH₃—CH(H₂PO₃)₂,1-hydroxyethyliden-1,1-diphosphonic acid (HEDP); N(CH₂—PO₃H₂)₃,aminotrimethylenphosphonic acid (ATMP);(H₂O₃P—CH₂)₂—N—CH₂—CH₂—N(H₂O₃P—CH₂)₂,ethylendiaminotetramethylenphosphonic acid (EDTMP);(H₂O₃P—CH₂)₂—N—CH₂—CH₂—N(CH₂PO₃H₂)—CH₂—CH₂—N(H₂O₃P—CH₂)2,diethylentriaminopentamethylenphosphonic acid (DTPMP)(H₂O₃P—CH₂)₂—N—(CH₂)₆—N(H₂O₃P—CH₂)₂,hexamethylendiaminotetramethylenphosphonic acid (HMDTMP). 19.Compositions according to claim 1, wherein the optional component 4) isselected from the following: MoS₂, WS₂ and graphite.
 20. Compositionsaccording to claim 1, optionally further diluted with water, and addedwith adhesion promoters, rheological modifiers to regulate theviscosity.
 21. Compositions according to claim 1, wherein the aqueousnanodispersion, or latex, of said homopolymer or modified PTFE, has aprimary particle diameter from 10 to 80 nm.
 22. Compositions accordingto claim 1, wherein the surfactant or surfactant mixtures is from 5 to30 parts by weight.
 23. Compositions according to claim 1, wherein theorganic or inorganic sequestrant capable to give bi- orpoly-coordination bands is from 0.4 to 10 parts by weight. 24.Compositions according to claim 1, wherein the solid lubricatingcompound is 0 to 50 parts by weight.
 25. Compositions according to claim1, wherein the solid lubricating compound is selected from sulphides andselenides of the transition elements belonging to the groups VB and VIBof the Element Periodic Table, and carbon compounds as graphite and C₆₀and C₇₀ fullerenes.
 26. Compositions according to claim 1, wherein thesulphides and selenides of the transition elements belonging to thegroups VB and VIB of the Element Periodic Table are molybdenum ortungsten.
 27. Compositions according to claim 2, wherein the modifiedPTFE nanoemulsions are in an amount up to 1% molar.
 28. Compositionsaccording to claim 4, wherein the styrene monomer is styrene. 29.Compositions according to claim 5, wherein the C₂-C₈ hydrogenatedfluoroolefins are vinyl fluoride (VF), vinylidene fluoride (VDF),trifluoroethylene, or hexafluoroisobutene.
 30. Compositions according toclaim 5, wherein the C₁-C₆ perfluoroalkyl is selected from CF₃, C₂F₅,and C₃F₇.
 31. Compositions according to claim 5, wherein the C₂-C₈chloro- and/or bromo- and/or iodo-fluoroolefins ischlorotrifluoroethylene (CTFE).
 32. Compositions according to claim 5,wherein the C₁-C₁₂ (per)fluorooxyalkyl having one or more ether groupsis perfluoro-2-propoxy-propyl.
 33. Compositions according to claim 5,wherein the fluorodioxoles are perfluorodioxoles.
 34. Compositionsaccording to claim 8, wherein the polycyclic hydrocarbons belonging tothe terpene class are β-pinene.
 35. Compositions according to claim 9,wherein NII=8-18.
 36. Compositions according to claim 9, whereinmII=2-18.
 37. Compositions according to claim 10, wherein R^(I) _(A) isa C₈-C₁₈ aliphatic hydrocarbon radical, both saturated and unsaturated,having a linear or branched chain selected from the group consistingof-a oleyl, stearyl, tridecyl, lauryl, and decyl radical. 38.Compositions according to claim 10, wherein M^(A) is an acid groupselected from the group consisting of COO— and SO₃—.
 39. Compositionsaccording to claim 12, wherein T is selected from the group consistingof —CF₃, —C₂F₅, —C₃F₇, —CF₂Cl, —C₂F₄Cl, and C₃F₆Cl.
 40. Compositionsaccording to claim 12, wherein M, in the range 350-1,000. 41.Compositions according to claim 14, wherein a, b are integers from 0 to2.
 42. Compositions according to claim 14, wherein qI is an integer from6 to
 25. 43. Compositions according to claim 14, wherein rI+sI is aninteger from 10 to
 44. Compositions according to claim 14, wherein therI/sI ratio is in the range 0.5-5.
 45. Compositions according to claim16, wherein carboxilic or phosphonic is two or four.
 46. Compositionsaccording to claim 17, wherein the polyphosphate is sodiumhexamethaphosphate Na₆P₆O₁₈.
 47. Compositions according to claim 17,wherein the amino-polycarboxylic acid is gluconic acid.
 48. Compositionsaccording to claim 20, wherein the rheological modifiers to regulate theviscosity are water-soluble polymers.
 49. Compositions according toclaim 5, wherein the fluorinated comonomers are selected fromhexafluoropropene (HFP).
 50. Compositions according to claim 17, whereinthe amino-polycarboxylic acids are EDTA.
 51. Compositions according toclaim 17, wherein the polyhydroxymonocarboxylic acids are preferablygluconic acid.
 52. Compositions according to claim 23, wherein R^(B)_(f) represents a (per)fluoropolyether chain having number averagemolecular weight comprised between from 500 to 1,300.